1. Field of the Invention
The invention relates to a radial piston machine, and more particularly, a radial piston machine that minimizes wear and power loss.
2. Description of the Related Art
Such a radial piston machine known, for instance, from DE 35 31 632 A1 comprises a rotor in the form of a cylinder block which accommodates a plurality of pistons and is rotatably disposed in a lifting ring (eccentric disk) fixed to the casing. The piston is guided in a radially extending cylinder bore of the rotor and is supported on the lifting ring via roll bodies in the form of cylindrical rollers. In radial piston machines of this type the force is transmitted from the eccentric disk to the pistons via the rollers rolling off the lifting cam. Such machines excel by a compact and cost-effective design as well as by their high-pressure capability.
From the general prior art it is furthermore known to provide a hydrostatic relieving field between the piston and the roller. For this purpose, at the front the cylindrical piston is provided with a pocket restricting the relieving field by the roller.
It is a drawback in such radial piston machines that the surface of the hydrostatic relieving field is smaller than the piston area. Therefore, the differential force must be mechanically absorbed. This causes a mixed friction resulting in wear, power loss and a poor starting moment of the radial piston machine.
Compared to this, the object underlying the invention is to provide a radial piston machine in which an improved hydrostatic support of the pistons with respect to the roll bodies is obtained.